C.Barnes Bristol Aircraft since 1910 (Putnam)

The Bristol T.T.A. and F.3A

   When Frank Barnwell returned to Filton in August 1915 he sought a technical assistant to work with him on new projects. He interviewed Leslie G. Frise, who had just graduated from Bristol University, and persuaded him to resign his R.N.A.S. commission to join the Company; together in September 1915 they laid out the preliminary design of a twin-engined local defence two-seater to a War Office requirement. Four R.A.F.4a engines of 150 h.p. were promised for two aircraft, and the aim was to design a compact biplane with a fuselage of the minimum size that would accommodate a pilot and gunner, giving the latter a maximum field of fire. Although both the crew could not be given equally good fields of vision, the pilot's location aft of the trailing edge gave a good view forward and downward. The gunner in the nose had an unobstructed field of fire in the forward hemisphere for two free-mounted Lewis guns and had five spare drums of ammunition, also a vertical camera. The pilot had a single Lewis gun firing aft, with three spare drums. Dual controls were fitted for emergency use only, with pedals in the front cockpit because the nose was too narrow for a normal rudder bar. The wings were of equal span and designed to fold back. Two sets of ailerons were designed, those actually constructed being of high aspect ratio. The tail unit comprised a single balanced rudder and flat tailplane of Scout D shape. The engine nacelles were midway between the wings and their rear fairings enclosed the oil and gravity fuel tanks. Below each nacelle was a small two-wheeled chassis of low drag, while the fuselage was protected by a fixed skid under the nose and a sprung tail-skid. The biplane, designated T.T. (Twin Tractor), promised to fulfil all the requirements, and was smaller than the F.E.4 designed at Farnborough to do the same job, which had a span of 75 ft.
   After tendering, the Company was informed that all R.A.F.4a engines were earmarked for the B.E.12 and R.E.8 programmes, and that 160 h.p. or 120 h.p. Beardmores would be issued instead. At length the smaller engines materialised, and in January 1916 the amended design was finished as T.T.A., two prototypes being ordered on 15 February 1916 at a price, less engines, of ?2,000 each. These identical aircraft, Nos. 1375 and 1376 (7750 and 7751), were test flown and accepted on 26 April and 27 May, respectively, by Capt. Hooper, Commanding Officer of the R.F.C. Acceptance Park at Filton. The first T.T.A. was flown to Upavon on 11 May for trials by A.LD. pilots and achieved a top speed of 87 m.p.h., and an initial rate of climb of nearly 400 ft. per minute, which was better than the F.E.4's performance in spite of the reduced power available, but the design was adversely criticised on other grounds and not recommended for squadron service.
   Concurrently with the building of the T.TA.'s the Admiralty released to the War Office a few 250 h.p. Rolls-Royce engines for experimental use, and the Company was invited to tender for an escort and anti-Zeppelin fighter using this power unit. Many firms submitted designs and Armstrong Whitworth, Bristol, Sopwith and Vickers all received orders for two prototypes each. The Bristol design, F.3A, was ordered on 16 May 1916 and sequence Nos. 1485 and 1486 were reserved, the corresponding R.F.C. serials being A612 and A613. The F.3A utilised many of the TTA.'s components, including wings, tail unit and rear fuselage with pilot's cockpit, but the contract was cancelled soon after being awarded, so it was never built. The landing gear was unorthodox and consisted of one T TA. chassis unit, suitably strengthened, under the fuselage with a small-wheeled outrigger under each wing-tip. Two gunners' nacelles were provided above the top wing, with a forward and a rearward gun in each, mounted on telescopic pillars swinging through 90 degrees to fire on the beam. Probably it was intended to install the Davis gun if this had developed satisfactorily. Duration of seven hours for night-fighting against Zeppelins was specified, but the project was abandoned as soon as reliable gun-synchronising gear became available.

SPECIFICATIONS AND DATA
   Types: T.T.A. and F.3A.
   Manufacturers: The British & Colonial Aeroplane Co. Ltd., Filton, Bristol

   Type T.T.A. F.3A
Power Plant Two 120 hp Beardmore One 250 hp Rolls-Royce
Span 53 ft 6 in 53 ft 6 in
Length 39 ft 2 in 36 ft 5 in
Height 12 ft 6 in 12 ft 11 in
Wing Area 817 sq ft 817 sq ft
Empty Weight 3,820 lb 3,400 lb
All-up Weight 5,100 lb 5,300 lb
Maximum Speed 87 mph -
Accommodation 2 3
Production 2 nil (2 cancelled)
Sequence Nos. 1375, 1376 (1485 1486)

P.Lewis The British Fighter since 1912 (Putnam)

In the course of September, 1915, design work had been initiated on an ambitious two-seat fighter biplane to be powered by twin engines and designated Bristol T.T. - Twin Tractor. Responsible for the project’s layout were F. S. Barnwell and L. G. Frise and in its general concept, together with the gunner in the nose and the pilot located behind the wings, the T.T. resembled the Vickers F.B.7 and F.B.8. The machine was of 53 ft. 6 in. span and was scheduled to employ a pair of 150 h.p. R.A.F.4a engines. Non-availability of these units forced the installation of two 120 h.p. Beardmores, the revision resulting in a new designation T.T.A. Two Lewis guns armed the front gunner and a third Lewis was installed for the pilot to fire to the rear. The T.T.A. was ready for its initial trials in May, 1916, and these were carried out by Capt. Hooper of the R.F.C.
   Like the two Vickers products, the Bristol T.T.A. lacked the primary requisites of a fighter and was too ponderous and low-powered to possess sufficient manoeuvrability, besides denying the pilot and gunner the quick communication between them which was so essential in a fighter. There was also negligible prospect of being able to fire the guns to the rear, which left the machine defenceless from that quarter; consequently, the pair of prototypes - 7750 and 7751 - were abandoned.
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   The F.K.11 was not proceeded with but another design from Armstrong Whitworth, the three-seat F.K.5, also exhibited some equally remarkable features. It was built as the result of a War Office requirement for a multi-seat, long-range escort and anti-Zeppelin fighter, a specification to which Vickers and Sopwith also constructed prototypes.
   The Bristol F.3A, a development of the T.T.A., using its aft fuselage, biplane wings and tailplane and the 250 h.p. Rolls-Royce Mk.I for power, was proposed to the same requirement but was abandoned. To give the F.3A’s gunners unrestricted field of fire, they were going to be installed in a pair of cockpits incorporated in the upper wings.

F.Mason The British Fighter since 1912 (Putnam)

Bristol Type 6 T.T.A.

   In September 1915, at much the same time that Rex Pierson at Vickers began work on his twin-engine F.B.8 gun carrier, Frank Barnwell started the design of an aircraft of similar concept. The Bristol designer, however, went further in attempting to provide what was intended to be a more effective armament by including a gun for rearward defence.
   His Type 6 twin-tractor aircraft (T.T., later to be termed the T.T.A.) was a very large three-bay biplane, scheduled to be powered by two 150hp RAF 4A engines; by the time the prototype began to take shape, however, all available engines of this type had been earmarked for the B.E.12, and Bristol had to make do with a pair of 120hp Beardmore engines. The crew consisted of a gunner in the nose, provided with a pair of free Lewis guns, and the pilot whose cockpit was behind the wings; a single rearward-firing free Lewis gun was to be fitted aft of the rear cockpit. Very large ailerons, each pair with two interconnecting struts, were fitted to upper and lower wings, while the tail unit was, in effect, an enlarged version of that on the Bristol Scout, being without a fixed fin. Fuel was carried in three main fuselage tanks and one behind each engine, with pressure feed being provided by a wind-driven pump.
   Two aircraft, Nos 7750 and 7751, were ordered at a price, less engines, of £2,000 apiece, and the first was flown by Captain C A Hooper, rfc, on 26 April, being followed by the second on 27 May. One was flown for evaluation at Upavon, but came in for criticism on several counts, including the pilot’s very poor field of vision, the impossibility of communication between the two crew members and the general sluggishness of the controls.
   However, like so many aspiring fighter aircraft designed before the end of 1915, the T.T.A. was overtaken by events with the arrival of the synchronized front gun, and further work on its development was abandoned.


   Type: Twin-engine, two-seat, three-bay biplane gun carrier.
   Manufacturer: The British & Colonial Aeroplane Co Ltd, Filton, Bristol.
   Powerplant: Two 120hp Beardmore engines driving two-blade propellers.
   Dimensions: Span, 53ft 6in; length, 39ft 2in; height, 12ft 6in; wing area, 817 sq ft. Weights: Tare, 3,820lb; all-up, 5,100lb.
   Performance: Max speed, 86.7 mph at sea level; climb to 6,000ft, 17 min 15 sec; service ceiling, 9,500ft.
   Armament: Two free-firing Lewis machine guns on nose cockpit, and a single rearward-firing Lewis gun on rear cockpit. (No armament fitted for trials.)
   Prototypes: Two, Nos 7750 and 7751 (first flown by Capt C A Hooper RFC on 26 April 1916). No production.

W.Green, G.Swanborough The Complete Book of Fighters

BRISTOL T.T.A. UK
  
   Designed by Frank Barnwell assisted by Leslie G Frise, the T.T.A. (Twin Tractor Model A) was intended to meet a requirement for a two-seat twin-engined local defence fighter, the gunner in the nose having an unobstructed field of fire for two free-mounted 0.303-in (7,7-mm) Lewis guns. Dual controls were fitted and the intended power plant comprised two 150 hp R.A.F.4a engines. In the event, non-availability of these engines resulted in the installation of two 120 hp six-cylinder Beardmore water-cooled engines in the two prototypes ordered. The first T.T.A. was flown in April 1916, but displayed poor lateral control and was adversely criticised on the grounds of poor pilot view. As by this time synchronising mechanisms for guns were becoming available, no further development of this category of aircraft was pursued.

Max speed, 87 mph (140 km/h) at sea level.
Time to 6,000 ft (1830 m), 21 min.
Empty weight, 3,820 lb (1 733 kg).
Loaded weight, 5,100 lb (2 313 kg).
Span, 53 ft 6 in (16,30 m).
Length, 39 ft 2 in (11,94 m).
Height, 12 ft 6 in (3,81 m).
Wing area, 817 sq ft (75,90 m ).

J.Bruce British Aeroplanes 1914-1918 (Putnam)

Bristol T.T.A

  SOON after the outbreak of war, it was realised that aerial combat was not only a possibility but an accomplished fact; and ways had to be sought to provide aircraft combining performance with effective fire power.
  In September, 1915, Frank Barnwell, assisted by L. G. Frise, began work on the design of a twin-engined two-seat fighter which was designated Bristol T.T., or Twin Tractor. Two engines were considered necessary to achieve a worthwhile performance, and the original design was for two 150 h.p. R.A.F. 4a engines. The gunner had two free Lewis guns, and occupied the nose cockpit from which he had a wide field of fire. The pilot sat behind the wings, and a single Lewis gun firing aft was provided for his use. Dual control was provided. The tail unit was generally similar in appearance to that of the Bristol Scout, and there were enormous ailerons.
  Petrol was carried in three main tanks in the fuselage, and pressure feed to the engines was maintained by a fan-driven pump. Two further tanks were fitted, one behind each engine. These were intended to be gravity tanks but were converted to pressure tanks.
  By the time the T.T. was ready for construction the output of R.A.F. 4a engines had been earmarked for B.E.12s. The Bristol design was therefore modified to have two Beardmore engines of either 120 h.p. or 160 h.p. Only the lower-powered engines became available, however, and the completed aircraft, re-designated T.T.A., was tested in May, 1916, by Captain Hooper, R.F.C. The engines turned in opposite senses.
  Later in May the T.T.A. went to Upavon to undergo official trials. Because it was underpowered its performance was not good; and it was adversely criticised on several grounds, but principally on the poor outlook from the pilot’s cockpit and the impossibility of fitting rearwards-firing guns. There was no kind of intercommunication between pilot and gunner; and the fuel system and poor lateral control were the subjects of adverse criticism.
  By the time the T.T.A. had flown, interrupter gears had become available, and Captain Barnwell was already looking ahead to the design which was to develop into the Bristol Fighter. There were therefore no misgivings over the abandonment of the T.T.A.
  The projected Bristol F.3A incorporated the wings, tailplane and rear fuselage of the T.T.A. The F.3A was designed to the same specification as the Armstrong Whitworth F.K.12, Sopwith LRTTr and Vickers F.B.11; and, like them, it was to have had the 250 h.p. Rolls-Royce engine. Two gunners were to have been accommodated in two cockpits mounted on the upper wing.


SPECIFICATION
  Manufacturers: The British & Colonial Aeroplane Co., Ltd., Filton, Bristol.
  Power: Two 120 h.p. Beardmore. Engines Nos. 2713F (starboard) and 3239F (port).
  Dimensions: Span.: 53 ft 6 in. Length: 39 ft 2 in. Height: 12 ft 6 in. Chord: 8 ft. Gap: 7 ft 10 1/2 in. Stagger: 11-8 in. Dihedral: 4°. Incidence: 2°. Span of tail: 17 ft 8 in. Airscrew diameter: 8 ft 11 in.
  Areas: Wings: 817 sqft. Tailplane: 81 sq ft. Elevators: 47 sq ft. Rudder: 33 sq ft.
  Weights and Performance: No. of Trial Report: M.37. Date of Trials: May 23rd and 24th, 1916. Place of trials: Central Flying School, Upavon. Airscrews used on trial: Type No. P.2359; maker’s series numbers B. & C. 2495 and 2498.
  Weight empty: 3,820 lb. Military load: 100 lb. Crew: 320 lb. Fuel and oil: 860 lb. Weight loaded: 5,100 lb. Maximum speed at ground level: 86-7 m.p.h.; at 2,000 ft: 85-8 m.p.h.; at 4,000 ft: 85-3 m.p.h.; at 6,000 ft: 85-6 m.p.h.; at 8,000 ft: 85 m.p.h. Climb to 1,000 ft: 3 min; to 2,000 ft: 6 min 45 sec; to 3,000 ft: 10 min 8 sec; to 4,000 ft: 13 min 30 sec; to 5,000 ft: 17 min 15 sec; to 6,000 ft: 21 min; to 7,000 ft: 25 min 52 sec; to 8,000 ft: 32 min 15 sec; to 9,000 ft: 39 min 45 sec; to 10,000 ft: 53 min 15 sec. Service ceiling: 9,500 ft.
  Tankage: Petrol: three main pressure tanks 93 gallons; two service pressure tanks 11 gallons each; total 115 gallons. Oil: 9 gallons. Water: 10 gallons.
  Armament: Two free Lewis machine-guns. One was fired by the gunner in the nose cockpit, the other by the pilot.
  Production: Two prototypes were built under Contract No. 87/A/330.
  Serial Numbers: 7750-7751.

H.King Armament of British Aircraft (Putnam)

T.T.A. This large two-seat fighter was first flown in the same month (May 1916) as the Avro Pike and there can be little doubt that it was initially intended to have been similarly armed. The 'one large gun' which was on one occasion mentioned as an alternative to the two Lewis guns with which the T.T.A. is generally associated may well have been of the Hotchkiss type, by then becoming established in French service. The pilot sat behind the wings, from which position he could sec little and probably accomplish less, for he was responsible for a rearward-firing free Lewis gun. For this he had three spare 47-round drums. The gunner, remote in the nose, had five drums for his Lewis gun.